Burning players can exit level
In Strife it is possible for the player to move around for a short time after dying when his death involves a fiery object as the inflictor of damage. The player's weapon goes away and is replaced with a pair of burning, waving arms.
During this state, changing weapons and using inventory items is impossible. However, activating cross-over and push-type linedefs is still allowed excepting one single type of line: the normal hub exit that passes the player seamlessly between two maps. This trigger is the only type in the game which actually checks if the player is alive before allowing activation.
However, there is an additional type of exit line in Strife: the deathmatch exit switch. In the game's stock map set, these deathmatch exit switches are usually hidden on the far side of each hub exit line, on posts which only rise up out of the ground courtesy of another line action which only activates if the game is in deathmatch mode.
Switches can be pressed in the Doom engine if the player is anywhere tangent to the line, however. It does not matter if the sector that the line borders is flush with the floor or not. This means that during the player burning death sequence, it is possible to run past the non-triggering hub exit line and, if its precise location is known beforehand, trigger the deathmatch exit switch.
Triggering an exit switch while in the burning death sequence leads to a suicide exit condition. This will spawn the player in the destination map with 100 health, no armor, no inventory items, no powerups including the comm unit that is used to communicate with Blackbird, and no objectives completed. If the player has not visited the destination map previously, he will spawn at the normal "player 1 start" object. If he has visited the level previously, he will find himself respawned at the precise last point where he left the level.
Most of the time this error would be fatal, leaving the player unable to progress further in the game, but there is at least one known point in the game where this can be used to sequence break. If this glitch is used to cross the exit line leading from the Sewers to the Castle, it is possible to skip the second part of the Sewers entirely and proceed directly to the main assault on the Castle. The player can regain his weapons and inventory by visiting the Training Facility and Audience Chamber. The previously earned quest flags and comm unit are not actually needed to progress further in the game after this point.
However, as a side effect of this glitch, the player must never re-enter the map which was exited while burning, or he will find himself rendered a ghost, unable to be hit by projectiles or trigger most linedefs. This limits the glitch's general usefulness even further.